Many people are farsighted and need to carry reading glasses to see things close up. For example, at a restaurant, many people require reading glasses to read the menu, verify the bill, and sign the check. This is especially true in low light conditions (e.g., in a dimly lit restaurant). In fact, some people also carry a small flashlight to increase their visibility in low light conditions.
However, carrying typical reading glasses, a flashlight, and a pen is cumbersome. Each item requires space in the person's pocket or purse, and each item must be located separately. In addition, handling all three items is awkward. For example, holding a flashlight with one hand while signing a check with the other hand does not leave a free hand to hold the check in place.